Electric motor assemblies including stator and/or rotor cooling

ABSTRACT

An electric motor assembly including a stator having a stator core and windings around the stator core is disclosed. The stator core has opposing ends and an outer surface extending between the opposing ends. The electric motor assembly also includes a housing having an inner surface enclosing at least a portion of the stator, and at least one fluid passage between the outer surface of the stator core and the inner surface of the housing. The fluid passage permits a coolant in the fluid passage to contact one or more portions of the outer surface of the stator core to remove heat from the stator core during operation of the electric motor assembly. Additional motor assemblies including stator and/or rotor cooling features are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/164,876, filed Jun. 21, 2011, which claims priority fromU.S. Provisional Patent Application No. 61/356,798, filed Jun. 21, 2010,and U.S. Provisional Patent Application No. 61/454,352, filed Mar. 18,2011. This application is related to U.S. patent application Ser. No.13/194,588, filed Jul. 29, 2011. The entire disclosures of each of theabove-referenced applications are hereby incorporated by referenceherein.

FIELD

The present disclosure relates to electric motor assemblies. Moreparticularly, the present disclosure relates to electric motorassemblies that include stator and/or rotor cooling.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

Electric motors typically convert electrical energy to mechanicalenergy. In converting the electrical energy to mechanical energy, heatis commonly generated. This generated heat, if not properly dissipatedfrom the motor, may degrade efficiency, damage the motor's components(including electrical windings, bearings, etc.), cause premature failureof the motor, etc.

Various cooling schemes, including fans, external cooling jackets, heatsinks, etc., have been used to attempt to cool electric motors and/ordissipate heat from electric motors.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

According to one aspect of the present disclosure, an electric motorassembly includes a stator including a stator core and windings aroundthe stator core. The stator core has opposing ends and an outer surfaceextending between the opposing ends. The motor assembly further includesa housing having an inner surface enclosing at least a portion of thestator, and at least one fluid passage between the outer surface of thestator core and the inner surface of the housing. The fluid passagepermits a coolant in the fluid passage to remove heat from the statorcore during operation of the electric motor assembly. The fluid passageincludes at least one flow disruptor to generate turbulence in thecoolant as the coolant flows through the fluid passage.

According to another aspect of this disclosure, an electric motorassembly includes a stator including a stator core and windings aroundthe stator core. The stator core has opposing ends and an outer surfaceextending between the opposing ends. The motor assembly further includesa housing having an inner surface enclosing at least a portion of thestator, and at least one fluid passage between the outer surface of thestator core and the inner surface of the housing. The fluid passage hasa substantially S-shaped configuration. The fluid passage permits acoolant in the fluid passage to remove heat from the stator core duringoperation of the electric motor assembly.

According to a further aspect of this disclosure, an electric motorassembly includes a stator including a stator core and windings aroundthe stator core. The stator core includes opposite first and secondends. The windings include end turns positioned at the first end of thestator core. The motor assembly further includes a housing enclosing atleast a portion of the stator, and a wall positioned between an end ofthe housing and the stator. The wall includes at least one orifice fordirecting coolant on the end turns for removing heat from the end turnsduring operation of the electric motor assembly.

According to yet another aspect of this disclosure, an electric motorassembly includes a bearing, a longitudinally extending shaft coupled tothe bearing, a rotor coupled to the shaft, a stator including a statorcore and windings around the stator core, and a housing having an innersurface enclosing at least a portion of the stator and having an endshield. The stator core has opposing ends and an outer surface extendingbetween the opposing ends. The windings include end turns positionedadjacent at least one of the opposing ends of the stator core. The motorassembly further includes a first fluid passage between the outersurface of the stator core and the inner surface of the housing, a wallpositioned between the end shield and the stator, a fluid chamberbetween the end shield and the wall, and a second fluid passageconnected in fluid communication with the fluid chamber for supplyingcoolant to the bearing to remove heat from the bearing and lubricate thebearing. The first fluid passage permits a coolant in the first fluidpassage to remove heat from the stator core during operation of theelectric motor assembly. The wall includes at least one orifice fordirecting coolant on the end turns for removing heat from the end turnsduring operation of the electric motor assembly. The fluid chamber isconnected in fluid communication with the first fluid passage forsupplying coolant to the at least one orifice.

According to still another aspect of this disclosure, an electric motorassembly includes a longitudinally extending shaft, and a rotor coupledto the shaft. The rotor has at least one internal fluid passageextending longitudinally from a first end of the rotor to a second endof the rotor. The motor assembly further includes an end plate coupledto the first end of the rotor. The end plate includes at least one fluidport in fluid communication with the at least one internal fluid passageof the rotor, and an impeller for drawing coolant into the fluid portand through the at least one internal fluid passage of the rotor whenthe rotor, the shaft and the end plate are rotated during operation ofthe electric motor assembly.

According to still another aspect of this disclosure, an electric motorassembly capable of being cooled with a coolant is provided. The motorassembly comprises a rotor rotatable about an axis, a stator including astator core and windings wound about the stator core, a housingenclosing at least a portion of the stator, and at least one orifice fordirecting coolant. The stator core includes opposite first and secondends spaced along the axis. The stator core presents an outer surfaceextending between the ends. The windings include end turns positioned atthe first end of the stator core. The housing includes an inner surfacethat cooperates with the outer surface of the stator core to define astator cooling passage through which coolant flows to remove heat fromthe stator core during operation of the assembly. The at least oneorifice is for directing coolant onto the end turns for removing heatfrom the end turns during operation of the assembly. The at least oneorifice is in fluid communication with the stator-cooling passage.

Further aspects and areas of applicability will become apparent from thedescription provided herein. It should be understood that variousaspects of this disclosure may be implemented individually or incombination with one or more other aspects, and in combination with oneor more other elements or features described herein and/or illustratedin the drawings. It should also be understood that the description andspecific examples in this disclosure are intended for purposes ofillustration only and are not intended to limit the scope of the presentdisclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a side view of an example electric motor assembly according toaspects of this disclosure.

FIG. 2 is an exploded side view of the example electric motor assemblyof FIG. 1.

FIG. 3 is a cutaway side view of the example electric motor assembly ofFIG. 1.

FIG. 4 is a bottom rear isometric cutaway view of the example electricmotor assembly of FIG. 1 with the rotor and shaft removed.

FIG. 5 is a top right isometric cutaway view of the example electricmotor assembly of FIG. 1 with the rotor and shaft removed.

FIG. 6 is a cutaway end view of the example electric motor assembly ofFIG. 1.

FIG. 7 is a close-up view of a portion of the stator of example electricmotor assembly of FIG. 1.

FIG. 8 is a cutaway end view of the example electric motor assembly ofFIG. 1 with the rotor and shaft removed.

FIG. 9 is an exploded side view of another example electric motorassembly according to at least one aspect of the present disclosure.

FIG. 10 is a cutaway side view of the example electric motor assembly ofFIG. 9 with the rotor and shaft removed.

FIG. 11 is a cutaway end view of the example electric motor assembly ofFIG. 9.

FIG. 12 is a cutaway side view of an example rotor assembly including arotor and a shaft according to at least one aspect of this disclosure.

FIG. 13 is a cutaway end view of the rotor assembly of FIG. 12.

FIG. 14 is a close-up view of a portion of the end plate, rotor andshaft of FIG. 12.

FIG. 15 is a cutaway side view of another example rotor assemblyincluding a rotor and a shaft according to at least one aspect of thisdisclosure.

FIG. 16 is a cutaway end view of the rotor assembly of FIG. 15.

FIG. 17 is a side isometric view of half of the rotor and end plate ofthe rotor assembly of FIG. 15.

FIG. 18 is a cutaway side view of yet another example rotor assemblyincluding a rotor and a shaft according to at least one aspect of thisdisclosure.

FIG. 19 is a cutaway end view of the rotor assembly of FIG. 18.

FIG. 20 is a cutaway side view of another example a rotor assemblyincluding a rotor and a shaft according to at least one aspect of thisdisclosure.

FIG. 21 is a top isometric view of one of the end plate of the assemblyin FIG. 20.

FIG. 22 is a bottom isometric view of one of the end plate of theassembly in FIG. 20.

FIG. 23 is an isometric view of the rotor assembly of FIG. 20 installedin an electric motor assembly.

FIG. 24 is an isometric view of the rotor assembly of FIG. 20 installedin an electric motor assembly with one of the rotor assembly's endplates removed.

FIG. 25 is a front side isometric view of the rotor assembly of FIG. 20installed in an electric motor assembly.

FIG. 26 is a rear side isometric view of the rotor assembly of FIG. 20installed in an electric motor assembly.

FIG. 27 is a cutaway side view of another example electric motorassembly according to aspects of the present disclosure.

FIG. 28 is a top right isometric cutaway view of the example electricmotor assembly of FIG. 27 with the rotor and shaft removed.

FIG. 29 is bottom rear isometric cutaway view of the example electricmotor assembly of FIG. 27 with the rotor and shaft removed.

FIG. 30 is a cutaway end view of the example electric motor assembly ofFIG. 27.

FIG. 31 is a cutaway side view of another example electric motorassembly according to aspects of the present disclosure.

FIG. 32 is a close-up view of portion A of the example electric motorassembly of FIG. 31.

FIG. 33 is a top isometric view of a bearing cap of the example electricmotor assembly of FIG. 31.

FIG. 34 is a cutaway side view of the bearing cap of FIG. 33.

FIG. 35 is a top plan view of the bearing cap of FIG. 33.

FIG. 36 is a cutaway right isometric view of another example electricmotor assembly according to aspects of the present disclosure.

FIG. 37 is a top right isometric view of a housing of the electric motorassembly of FIG. 36.

FIG. 38 is a top left isometric view of the housing of FIG. 37.

FIG. 39 is a cutaway right isometric view of the electric motor assemblyof FIG. 36.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

According to one aspect of the present disclosure, an electric motorassembly includes a stator having a stator core and windings around thestator core. The stator core has opposing ends and an outer surfaceextending between the opposing ends. The electric motor assembly alsoincludes a housing having an inner surface enclosing at least a portionof the stator, and at least one fluid passage between the outer surfaceof the stator core and the inner surface of the housing. The fluidpassage permits a coolant in the fluid passage to remove heat from thestator core during operation of the electric motor assembly. The fluidpassage includes at least one flow disruptor to generate turbulence inthe coolant as the coolant flows through the fluid passage.

The fluid passage may permit coolant in the fluid passage to contact oneor more portions of the outer surface of the stator. Alternatively,coolant in the fluid passage may be separated from the outer surface ofthe stator by, for example, a thermally conductive fluid passage wall,etc.

The stator core may be constructed by any suitable manner ofconstruction. For example, the stator may include a plurality of statorlamination having outer edges. The fluid passage may be configured topermit a coolant in the fluid passage to contact one or more outeredges.

The housing may include a fluid inlet and a fluid outlet in fluidcommunication with the fluid passage. The housing may include a fluidcollection area adjacent the fluid outlet. The fluid collection area andthe fluid outlet may be positioned below the stator.

The fluid passage may have an S-shaped configuration. Alternatively, thefluid passage may have another configuration, including, for example, astraight, spiral or rectangular configuration. The fluid passage mayhave a symmetrical configuration or a non-symmetrical configuration.

The fluid passage may extend along a central portion of the stator core.Alternatively, or additionally, the fluid passage may extend along aportion of the stator core that is not a central portion, including, forexample, one or more portions alongside a central portion of the statorcore.

The assembly may include two fluid passages between the outer surface ofthe stator core and the inner surface of the housing. Each fluid passagemay permit a coolant therein to contact one or more portions of theouter surface of the stator core for removing heat from the stator coreduring operation of the electric motor assembly. The two fluid passagesmay extend around opposite sides of the stator core. The assembly mayalso include more than two such fluid passages between the outer surfaceof the stator core and the inner surface of the housing.

One or more portions of the housing inner surface may engage the outersurface of the stator core. The housing inner surface may have arecessed channel extending therein. The outer surface of the stator coreand the recessed channel of the housing inner surface may define the atleast one fluid passage.

The stator windings may include end turns. The electric motor assemblymay further include at least one orifice for spraying coolant on the endturns during operation of the electric motor assembly.

The assembly may include a rotor having at least one fluid passageextending along or through the rotor. The rotor fluid passage may permita coolant therein to contact one or more portions of the rotor forremoving heat from the rotor during operation of the electric motorassembly.

The assembly may include an end plate coupled to an end of the rotor.The end plate may include at least one fluid port in fluid communicationwith the rotor fluid passage. The end plate may include an impeller(sometimes referred to as a fan) that rotates with the rotor assemblyfor drawing coolant into the fluid port and through the rotor fluidpassage when the rotor and the end plate are rotated during operation ofthe electric motor assembly.

According to another aspect of the present disclosure, an electric motorassembly includes a stator having a stator core and windings around thestator core. The stator core has opposing ends and an outer surfaceextending between the opposing ends. The electric motor assembly alsoincludes a housing having an inner surface enclosing at least a portionof the stator, and at least one fluid passage between the outer surfaceof the stator core and the inner surface of the housing. The fluidpassage has an S-shaped configuration. The fluid passage permits acoolant in the fluid passage to remove heat from the stator core duringoperation of the electric motor assembly.

The fluid passage may include a flow disruptor to generate turbulence inthe coolant as the coolant flows through the fluid passage.

The fluid passage may permit coolant in the fluid passage to contact oneor more portions of the outer surface of the stator to remove heat fromthe stator core during operation of the electric motor assembly.

The stator core may be constructed by any suitable manner ofconstruction. For example, the stator may include a plurality of statorlamination having outer edges. The fluid passage may be configured topermit a coolant in the fluid passage to contact one or more outeredges.

The housing may include a fluid inlet and a fluid outlet in fluidcommunication with the fluid passage. The housing may include a fluidcollection area adjacent the fluid outlet. The fluid collection area andthe fluid outlet may be positioned below the stator. The fluid passagemay have a symmetrical configuration or a non-symmetrical configuration.In any given embodiment, portions of the housing that surround the fluidpassage may contact and support the outer surface of the stator 104.Preferably, the contacting portions are spaced around the circumferenceof each section of the stator. As a result, the housing contacts andsupports the outer surface of the stator in multiple locations about thecircumference of the stator along the entire length of the stator.

Preferably, the fluid passage extends between the opposite ends of thestator for removing heat along the entire length of the stator.Alternatively, the fluid passage may extend along only a central (orother) portion of the stator core.

The assembly may include two fluid passages between the outer surface ofthe stator core and the inner surface of the housing. Each fluid passagemay permit a coolant therein to contact one or more portions of theouter surface of the stator core for removing heat from the stator coreduring operation of the electric motor assembly. The two fluid passagesmay extend around opposite sides of the stator core. The assembly mayalso include more than two such fluid passages between the outer surfaceof the stator core and the inner surface of the housing.

One or more portions of the housing inner surface may engage the outersurface of the stator core. The housing inner surface may have arecessed channel extending therein. The outer surface of the stator coreand the recessed channel of the housing inner surface may define the atleast one fluid passage.

The stator windings may include end turns. The electric motor assemblymay further include at least one orifice for spraying coolant on the endturns during operation of the electric motor assembly.

The assembly may include a rotor having at least one fluid passageextending along or through the rotor. The rotor fluid passage may permita coolant therein to contact one or more portions of the rotor forremoving heat from the rotor during operation of the electric motorassembly.

The assembly may include an end plate coupled an end of the rotor. Theend plate may include at least one fluid port in fluid communicationwith the rotor fluid passage. The end plate may include an impeller fordrawing coolant into the fluid port and through the rotor fluid passagewhen the rotor and the end plate are rotated during operation of theelectric motor assembly.

According to another aspect of the present disclosure, an electric motorassembly includes a stator including a stator core and windings aroundthe stator core. The stator core includes opposite first and secondends. The windings include end turns positioned at the first end of thestator core. The assembly includes a housing enclosing at least aportion of the stator. The assembly also includes a wall positionedbetween the housing and the stator. The wall includes at least oneorifice for directing coolant on the end turns for removing heat fromthe end turns during operation of the electric motor assembly.

The orifice may be adapted to spray coolant on the end turns duringoperation of the electric motor assembly. The orifice may be adapted tospray coolant on one or more different portions of the end turns. Forexample, the orifice may be adapted to spray coolant on an outer side ofthe end turns during operation of the electric motor assembly.Alternatively, or additionally, the orifice may be adapted to spraycoolant on an inner side of the end turns during operation of theelectric motor assembly. Alternatively, or additionally, the orifice maybe adapted to spray coolant on a face of the end turns during operationof the electric motor assembly. The assembly may include a plurality oforifices for directing coolant on an outer side, an inner side and aface of the end turns during operation of the electric motor assembly.

The windings may include end turns positioned at the second end of thestator core, and the assembly may include at least one orifice fordirecting coolant on the end turns positioned at the second end of thestator core for removing heat therefrom during operation of the electricmotor assembly. The orifice may be adapted to spray coolant on one ormore different portions of the end turns (e.g., an inner side, an outerside, a face, etc.). The assembly may include a plurality of orificesfor directing coolant on an outer side, an inner side and a face of theend turns positioned at the second end of the stator core.

The housing may include an end shield and the wall may be positionedbetween the end shield and the stator. The assembly may include aplurality of orifices for directing coolant on the end turns duringoperation of the electric motor assembly. The plurality of orifices maybe positioned on the wall. The wall may be contoured.

The assembly may also include a fluid chamber between the end shield andthe wall for supplying coolant to the at least one orifice. The assemblymay include at least one fluid passage between the outer surface of thestator core and an inner surface of the housing. The fluid passagepermits a coolant in the fluid passage to contact one or more portionsof the outer surface of the stator core for removing heat from thestator core during operation of the electric motor assembly. The fluidpassage is connected in fluid communication with the fluid chamberbetween the end shield and the wall.

The housing may include a fluid inlet and a fluid outlet in fluidcommunication with the at least one orifice. The housing may include afluid collection area adjacent the fluid outlet. The fluid collectionarea and the fluid outlet may be positioned below the stator.

The assembly may include a rotor having at least one fluid passageextending along or through the rotor. The rotor fluid passage permits acoolant therein to contact one or more portions of the rotor forremoving heat from the rotor during operation of the electric motorassembly.

According to another aspect of the present disclosure, an electric motorassembly includes a longitudinally extending shaft, and a rotor coupledto the shaft. The rotor includes at least one internal fluid passageextending longitudinally from a first end of the rotor to a second endof the rotor. The assembly includes an end plate coupled to the firstend of the rotor. The end plate includes at least one fluid port influid communication with the at least one internal fluid passage of therotor, and an impeller for drawing coolant into the fluid port andthrough the at least one internal fluid passage of the rotor when therotor, the shaft and the end plate are rotated during operation of theelectric motor assembly.

The rotor may include more than one internal fluid passages. Forexample, the rotor may include a plurality of internal fluid passagesextending longitudinally from a first end of the rotor to a second endof the rotor.

The end plate may include a plurality of fluid ports each in fluidcommunication with at least one of the internal fluid passages of therotor.

The end plate may include an impeller for drawing coolant into the fluidports and through the internal fluid passages when the rotor, the shaftand the end plate are rotated.

According to another aspect of the present disclosure, an electric motorassembly includes a longitudinally extending shaft coupled to a bearingand a rotor coupled to the shaft. The assembly includes a statorincluding a stator core and windings around the stator core. The statorcore has opposing ends and an outer surface extending between theopposing ends. The assembly includes a housing having an inner surfaceenclosing at least a portion of the stator and having an end shield. Theassembly includes at least one fluid passage between the outer surfaceof the stator core and the inner surface of the housing. The fluidpassage permits a coolant in the fluid passage to remove heat from thestator core during operation of the electric motor assembly. Theassembly includes a wall positioned between the end shield and thestator. The wall includes at least one orifice for directing coolant onthe end turns for removing heat from the end turns during operation ofthe electric motor assembly. The assembly includes a fluid chamberbetween the end shield and the wall. The fluid chamber is connected influid communication with the fluid passage for supplying the coolant tothe at least one orifice. The assembly includes a fluid passageconnected in fluid communication with the fluid chamber for supplyingthe coolant to the bearing to remove heat from the bearing and lubricatethe bearing.

The assembly may include a bearing cap adjacent the bearing. The bearingcap may include at least one orifice and the bearing cap orifice may bein fluid communication with the fluid chamber for directing the coolantto the rotor for removing heat from the rotor during operation of theelectric motor assembly.

The rotor may include at least one internal fluid passage extendinglongitudinally from a first end of the rotor to a second end of therotor. The assembly may include an end plate coupled to the first end ofthe rotor. The end plate may include at least one fluid port in fluidcommunication with the at least one internal fluid passage of the rotor.The end plate may include an impeller for drawing the coolant and airinto the fluid port and through the at least one internal fluid passageof the rotor when the rotor, the shaft and the end plate are rotatedduring operation of the electric motor assembly.

The housing may include a fluid inlet and a fluid outlet in fluidcommunication with the fluid passage. The fluid collection area and thefluid outlet may be positioned below the stator.

The various aspects discussed herein may be employed individually or incombination, and may be incorporated in various types of electric motorsincluding, for example, permanent magnet motors, switched reluctancemotors, etc. Exemplary embodiments of electric motor assemblies andcomponents (e.g., various rotors, end plates, housings, etc.) will bediscussed with reference to FIGS. 1-39. It should be understood,however, that other motor assemblies, components, etc. may be used toembody the aspects disclosed herein without departing from the scope ofthis disclosure.

An example electric motor assembly, generally indicated by referencenumeral 100, according to one or more aspects of the present disclosurewill be described with reference to FIGS. 1-8.

The assembly 100 includes a housing 102 and a stator 104. The stator 104includes a stator core 106 with windings having end turns 108 around thestator core 106. The stator core includes an outer surface 110. In theparticular example of FIG. 1, the motor assembly 100 is an internalpermanent magnet (IPM) motor with permanent magnets imbedded in thestator core 106.

The housing 102 includes an inner surface 112 (best seen in FIGS. 4 and5). The inner surface 112 encloses the stator 104. Although theillustrated inner surface 112 encloses all of the stator 104, thehousing 102 may include an inner surface 112 that encloses less than allof the stator 104.

The inner surface 112 of the housing 102 engages (e.g., contacts,couples with, is connected to, etc.) the outer surface 110 of the statorcore 106. A fluid passage 114 is cooperatively defined by the outersurface 110 of the stator core 106 and a recessed channel 115 in theinner surface 112 of the housing 102. The fluid passage 114 permits acoolant (not illustrated) in the fluid passage 114 to contact portionsof the outer surface 110 of the stator core 106 to remove heat from thestator core 106 during operation of the electric motor assembly 100.

The coolant may be any suitable fluid for transferring heat. The coolantmay be, for example, oil, air, a mixture of oil and air, etc.

The illustrated recessed channel 115, and accordingly the fluid passage114, is generally S-shaped traversing circumferentially and axiallyaround at least part of the housing 102 along a central portion of thestator core 106. The fluid passage 114 may traverse around the entirecircumference of the housing 102, or may traverse less than the entirecircumference of the housing 102. Additionally, the fluid passage 114may be oriented along the axial length of the housing 102 (e.g., rotatedninety degrees from the orientation shown in FIG. 4). The fluid passage114 may be located offset from a central portion of the stator core 106.Alternatively, or additionally, the fluid passage 114 may traverse thehousing both circumferentially and axially (i.e., lengthwise), with noparticular direction (e.g., random, meandering, etc.), etc.Additionally, the fluid passage 114 may have any suitable shape,including serpentine and non-serpentine shapes. The fluid passage 114may be symmetrical, asymmetrical, a combination of symmetrical andasymmetrical, etc. Additionally, or alternatively, the assembly 100 mayinclude more than one fluid passage 114. For example, in the embodimentshown in FIG. 4, there is a first fluid passage 114 on one half of thehousing 102, and a second fluid passage (not shown) on the other half ofthe housing 102. Collectively, these two fluid passages extend aroundboth sides of the stator core 106. In some embodiments, the overallwidth of the recessed channel 115 is slightly less than the axial lengthof the stator core 106. As a result, the channel 115 winds back andforth between the opposite ends of the stator core 106 for removing heatalong the entire axial length of the stator core 106.

The stator 104 is a laminated stator. The stator core 106 is constructedof a plurality of stator laminations (not separately illustrated)laminated together. The stator laminations have outer edges (whichcooperatively form at least part of the outer surface 110 of the statorcore 106). The fluid passage 114 is configured to permit coolant in thefluid passage 114 to contact the outer edges of the stator laminations.

The assembly 100 includes a fluid inlet 116 in fluid communication withthe fluid passage 114. The assembly 100 also includes a fluid outlet 118in fluid communication with the fluid passage 114. A fluid collectionarea 120 is located adjacent the fluid outlet 118. The fluid outlet 118and the fluid collection area 120 are located below the stator 104.

During operation of the electric motor assembly 100, coolant enters theassembly 100 through the fluid inlet 116 and flows through the fluidpassage 114 toward the fluid outlet 118. While flowing in the fluidpassage 114, the coolant is in direct contact with the outer surface 110of the stator core 106. More particularly, the coolant is in directcontact with the stator laminations. Heat is transferred by this contactfrom the stator core 106 to the coolant. Generally, the coolant exitsthe fluid passage 114 through the fluid outlet 118. Some of the coolantmay be directed elsewhere in the assembly 100 instead of exiting thefluid outlet 118, as will be discussed below. The coolant that exits thefluid outlet 118 is returned to the fluid inlet 116. During therecirculation to the fluid inlet 116, the coolant may be processed withat least one heat exchanger to release at least some of the heat thecoolant received from the stator core 106. Any suitable process forlowering the temperature of the coolant by allowing the coolant torelease heat may be used. For example, the coolant may be cooled using aradiator, a fan, thermally conductive tubing, a heat sink, a combinationof such cooling techniques, etc.

As shown in FIG. 6, portions 117 of the housing 102 that surround thefluid passage 114 contact and support the outer surface of the stator104. Preferably, the contacting portions 117 are evenly spaced aroundalmost the entire circumference of the stator 104. While FIG. 6illustrates a cross

sectional view through one portion of the stator 104, it should beunderstood that similar portions of the housing 102 are evenly spacedaround the circumference of other portions of the stator. As a result,the housing contacts and supports the outer surface of the stator inmultiple locations about the circumference of the stator along theentire length of the stator.

The assembly 100 includes a first end shield 122 and a second end shield124. A first wall 126 is positioned between the first end shield 122 andthe stator 104. A second wall 128 is positioned between the second endshield 124 and the stator 104. The first wall 126 and the first endshield 122 cooperatively define a first fluid chamber 130 and the secondwall 128 and the second end shield 124 cooperatively define a secondfluid chamber 132. Each of the first and second walls 126, 128 includesa plurality of orifices 134 (e.g., holes, slots, openings, etc.). Thewalls 126, 128 may include more or fewer orifices 134 than areillustrated in FIG. 8 and/or the configuration of orifices 134 maydiffer.

In operation of the assembly 100, coolant flows into the first andsecond fluid chambers 130, 132 and through the orifices 134. Theorifices 134 are configured (e.g., shaped, sized, aimed, etc.) to directthe coolant onto the end turns 108 of the stator 104 to remove heat fromthe end turns 108. The orifices 134 may be configured to spray coolanton an outer side 136 of the end turns 108, on an inner side 138 of theend turns 108, and/or on a face 140 of the end turns 108.

The coolant to be sprayed by the orifices 134 is some of the samecoolant that flows through the fluid passage 114. As discussed above,coolant flows through the fluid passage 114 toward the fluid outlet 118.Most of the coolant exits the fluid passage 114 through the fluidcollection area 120 and the fluid outlet 118. Some or all of thecoolant, however, is diverted into a transfer port 142 located near thefluid outlet 118. The transfer port 142 is in fluid communication withat least one of the fluid chambers 130, 132. For example, the transferport 142 illustrated in FIG. 5 transfers coolant to the first fluidchamber 130. A similar transfer port 142 on the other half of thehousing 102 will provide coolant to the second fluid chamber 132.Alternatively, a single transfer port (and/or more than two transferports) may provide coolant to both fluid chambers 130, 132. Similarly,more than one transfer port may provide coolant to a single fluidchamber 130, 132. Alternatively, or additionally, coolant may beprovided to the first and second fluid chambers 130, 132 separately fromthe coolant in the fluid passage 114.

Coolant sprayed onto the end turns 108 drips, splashes, etc. off the endturns 108 and is collected by drainage ports 143. The drainage ports 143direct the coolant into the fluid collection area 120. Alternatively, oradditionally, coolant sprayed by the orifices 134 may be collectedseparately from coolant passed through the fluid passage 114.

The coolant is forcefully circulated through the assembly 100 (and moreparticularly, through the fluid passage 114, transfer port 142, etc.)using pressure. The pressure and speed of the coolant may be varied toachieve desired cooling, desired spray from the orifices 134, etc.Alternatively, or additionally, the coolant may be circulated by anyother suitable means (including, e.g., by gravity).

The cooling features discussed above are generally directed to coolingthe stator 104. The assembly 100 may also include features generallydirected to cooling a rotor 144. For example, the rotor 144 includes afluid passage 146 extending through part of the rotor 144. Coolant maytravel through the fluid passage 146 to contact one or more portions ofthe rotor 144 to remove heat from the rotor 144 during operation of theassembly 100. Other suitable rotors, including rotors without a fluidpassage 146, rotors according to other embodiments discussed herein,etc., may be used in the assembly 100 without departing from the scopeof this disclosure.

The assembly 100 includes first and second bearings 148, 150. The firstend shield 122 includes a first fluid passage 152 connected in fluidcommunication with the first fluid chamber 130 for supplying coolant tothe first bearing 148 to remove heat from the first bearing 148 andlubricate the first bearing 148. The second end shield 124 includes asecond fluid passage 154 connected in fluid communication with thesecond fluid chamber 132 for supplying coolant to the second bearing 150to remove heat from the second bearing 150 and lubricate the secondbearing 150.

Another example embodiment of an electric motor assembly 200 isillustrated in FIGS. 9-11. The assembly 200 includes a housing 202, afirst end shield 222 and a second end shield 224. The assembly 200 alsoincludes a stator 204 with a stator core 206 including an outer surface210 and windings having end turns 208 around the stator core 206. Theassembly 200 also includes a rotor 244 positioned within the stator 204.

The housing 202 includes an inner surface 212. The inner surface 212encloses the stator 204. The inner surface 212 of the housing 202engages (e.g., contacts, couples with, is connected to, etc.) the outersurface 210 of the stator core 206. A fluid passage 214 is cooperativelydefined by the outer surface 210 of the stator core 206 and a recessedchannel 215 in the inner surface 212 of the housing 202. The fluidpassage 214 permits a coolant (not illustrated) in the fluid passage 214to contact portions of the outer surface 210 of the stator core 206 toremove heat from the stator core 206 during operation of the electricmotor assembly 200. The coolant may be any suitable fluid fortransferring heat. The coolant may be, for example, oil, air, a mixtureof oil and air, etc.

The illustrated recessed channel 215, and accordingly the fluid passage214, is generally S-shaped and traverses circumferentially and axiallyaround at least part of the housing 202 along a central portion of thestator core 206. Lines 246 indicate approximate outer boundaries of thestator core 206 in FIG. 10. The recessed channel 215 may traverse aroundthe entire circumference of the housing 202, or may traverse less thanthe entire circumference of the housing 202. Additionally, the recessedchannel 215 may be oriented along the length of the housing 202 (e.g.,substantially perpendicular to the illustrated recessed channel 215).The recessed channel 215 may be located offset from a central portion ofthe stator core 206. Alternatively, or additionally, the recessedchannel 215 may traverse the housing both circumferentially andlengthwise, with no particular direction (e.g., random, meandering,etc.), etc. Additionally, the recessed channel 215 may have any suitableshape and is not limited to the serpentine shape shown in FIG. 10. Therecessed channel 215 may be symmetrical, asymmetrical, a combination ofsymmetrical and asymmetrical, etc. Additionally, or alternatively, theassembly 200 may include more than one recessed channel 215. Forexample, there may be a recessed channel 215 on each half of the housing202 (e.g., around opposite sides of the stator core 206).

The stator 204 is a laminated stator. The stator core 206 is constructedof a plurality of stator laminations (not separately illustrated)laminated together. The stator laminations have outer edges (whichcooperatively form at least part of the outer surface 210 of the statorcore 206). The fluid passage 214 is configured to permit coolant in thefluid passage 214 to contact the outer edges of the stator laminations.

As seen in FIG. 10, the housing 202 includes several fluid grooves 248extending from the recessed channel 215. The fluid grooves 248 are influid communication with the recessed channel 215. Coolant flowingthrough the fluid passage 214 can flow into and through the fluidgrooves 248. Portions of the fluid grooves 248 (e.g., the part of thefluid grooves 248 located between the lines 246) are located adjacentthe outer surface 210 of the stator core 206. Accordingly, these partsof the fluid grooves 248 and the outer surface 210 of the stator core206 cooperatively define an enclosed fluid groove to retain coolant inthe fluid grooves 248 and through which the coolant may flow. Portions250 of the fluid grooves 248 (sometime referred to herein as orifices)extend beyond the ends of the stator core 206 (marked by the lines 246).Coolant in the fluid grooves 248 is not retained in the fluid grooves248 by the stator core 206 in these portions 250 (sometime referred toherein as orifices 250). Accordingly, the coolant is free to exit thefluid grooves 248 by the orifices 250. The fluid grooves 248 (includingthe orifices 250) are configured (e.g., shaped, sized, positioned,oriented, etc.) to spray coolant from the grooves 248 onto the end turns208 of the stator 204 during operation of the assembly 200.

The assembly 200 includes a fluid inlet 216 in fluid communication withthe fluid passage 214. The assembly 200 also includes a fluid outlet 218in fluid communication with the fluid passage 214. A fluid collectionarea 220 is located adjacent the fluid outlet 218. The fluid outlet 218and the fluid collection area 220 are located below the stator 204.

During operation of the electric motor assembly 200, coolant enters theassembly 200 through the fluid inlet 216 and flows through the fluidpassage 214 toward the fluid outlet 218. While flowing in the fluidpassage 214, the coolant is in direct contact with the outer surface 210of the stator core 206. More particularly, the coolant is in directcontact with the stator laminations. Heat is transferred by this contactfrom the stator core 206 to the coolant. Generally, the coolant exitsthe fluid passage 214 through the fluid outlet 218 and the fluidcollection area 220. Some of the coolant is directed through the fluidgrooves 248 to be sprayed from the orifices 250 to cool the end turns208, as discussed above. The coolant that exits the fluid outlet 218 isreturned to the fluid inlet 216. During the recirculation to the fluidinlet 216, the coolant may be processed with at least one heat exchangerto release at least some of the heat the coolant received from thestator core 206. Any suitable process for lowering the temperature ofthe coolant by allowing the coolant to release heat may be used. Forexample, the coolant may be cooled using a radiator, a fan, thermallyconductive tubing, a heat sink, a combination of such coolingtechniques, etc.

The coolant is forcefully circulated through the assembly 200 (and moreparticularly, through the fluid passage 214 and the grooves 248) usingpressure. The pressure and speed of the coolant may be varied to achievedesired cooling, desired spray from the orifices 250, etc.Alternatively, or additionally, the coolant may be circulated by anyother suitable means (including, e.g., by gravity).

An example embodiment of a rotor assembly 300 for use in an electricmotor assembly is illustrated in FIGS. 12-14. The rotor assembly 300 maybe used in electric motor assembly 100 or electric motor assembly 200,or in any other suitable motor assembly, with or without the statorcooling features disclosed herein.

The rotor assembly 300 includes a rotor 302 and a shaft 304 coupled tothe rotor 302.

The rotor 302 includes four keyways 306A, 3068, 306C and 3060 (sometimescollectively and/or generically referred to herein as keyways 306)extending longitudinally through the rotor 302. One or more of thekeyways 306 are typically used to couple the rotor 302 to the shaft 304.As shown in FIG. 13, keyway 306C includes a key 308 within keyway 306Cto couple the rotor 302 to the shaft 304. The remaining keyways 306A,3068, 3060 are not used for coupling the rotor 302 to the shaft 304using a key 308. The key 308 may be a separate component or may be partof the shaft 304. More than one keyway may be used, in conjunction witha key 308, to couple the shaft 304 to the rotor 302 and the rotor 302may include more or fewer keyways 306.

The shaft 304 includes two internal fluid paths 310A and 3108 (sometimescollectively and/or generically referred to herein as internal fluidpath 310) extending longitudinally through part of the shaft 304. Theinternal fluid paths 310A and 3108 may be considered to make up a singleinternal fluid path 310 and/or may each be considered a separateinternal fluid path 310. Alternatively, the shaft 304 may include asingle internal fluid path 310, or more than two internal fluid paths310. The internal fluid paths 310A, 3108 are coupled in fluidcommunication with an input port 312 located at one end of the shaft304. Internal fluid path 310A includes an exit port 314A and internalfluid path 3108 includes a fluid exit port 3148 (sometimes collectivelyand/or generically referred to herein as fluid exit port 314). Theinternal fluid paths 310 each include a first portion 316 extendingsubstantially longitudinally through the rotor 302 and a second portion318 extending substantially radially through the rotor 302 between thefirst portion 316 and the fluid exit port 314. The internal fluid paths310 are illustrated with a generally circular cross-section, but mayhave any suitable cross-section, including, for example, an ellipticalcross

section.

The keyways 306A and 3068 are coupled in fluid communication to internalfluid paths 310 via the exit ports 314. Accordingly, coolant may flowthrough internal fluid path 310A and into (and through) keyway 306A. Thecoolant contacts portions of the rotor 302 in the keyway 306A to removeheat from the rotor 302 during operation of an electric machineincorporating the rotor assembly 300. Similarly, coolant may flowthrough internal fluid path 3108 and into (and through) keyway 3068. Thecoolant contacts portions of the rotor 302 in the keyway 3068 to removeheat from the rotor 302 during operation of an electric machineincorporating the rotor assembly 300.

The rotor assembly 300 includes two end plates 320 coupled to opposingends of the rotor 302. Each end plate 320 cooperatively defines with therotor 302 a fluid passage 322 between the end of the rotor 302 and theend plate 320. The fluid passage 322 is connected in fluid communicationwith the keyways 306 to permit coolant in the keyways 306 to contact theend of the rotor 302 during operation of an electric machineincorporating the rotor assembly 300.

Each end plate 320 includes orifices 324 extending through the end plate320. The orifices 324 are in fluid communication with the fluid passage322 to permit coolant flowing through the rotor assembly 300 to exit therotor assembly 300. Although illustrated with two such end plates 320with orifices 324, the rotor 302 may include a single end plate 320, mayinclude one end plate 320 with orifices 324 and another end plate 320without orifices 324, may include endplate(s) 320 with more or fewerorifices 324, etc.

With reference to one side of the rotor assembly 300, in operation,coolant is pumped into the internal fluid path 310A in the shaft 304.The coolant travels longitudinally down the shaft 304 and then radiallytoward the exit port 314A. Coolant then enters the keyway 306A andtravels through the keyway 306A toward both ends of the rotor 302.During this passage through the keyway 306A, the coolant is in contactwith the rotor 302 and removes some heat from the rotor 302. The coolantenters the fluid passage 322 and contacts the ends of the rotor 302,removing additional heat from the rotor 302. The coolant is thenexpelled from the rotor assembly 300 through the orifices 324 in the endplates 320. The expelled coolant is collected (such as via drainageports 143 if the rotor assembly 300 were used in electric motor assembly100) and recirculated to the input port 312. During the recirculation,the coolant may be processed to release at least some of the heat thecoolant received from the rotor 302. Any suitable process for loweringthe temperature of the coolant by allowing the coolant to release heatmay be used. For example, the coolant may be cooled using a radiator, afan, thermally conductive tubing, a heat sink, a combination of suchcooling techniques, etc.

Another example embodiment of a rotor assembly 400 for use in anelectric motor assembly is illustrated in FIGS. 15-17. The rotorassembly 400 may be used in electric motor assembly 100 or electricmotor assembly 200, or in any other suitable motor assembly, with orwithout the stator cooling features disclosed herein.

The rotor assembly 400 includes a rotor 402 and a shaft 404 coupled tothe rotor 402.

The rotor 402 includes four keyways 406 extending longitudinally throughthe rotor 402. One or more of the keyways 406 are typically used tocouple the rotor 402 to the shaft 404. As shown in FIG. 16, one keyway406 includes a key 408 within the keyway 406 to couple the rotor 402 tothe shaft 404. The remaining keyways 406 are not used for coupling therotor 402 to the shaft 404 using a key 408. The key 408 may be aseparate component or may be part of the shaft 404. More than one keywaymay be used, in conjunction with a key 408, to couple the shaft 404 tothe rotor 402 and the rotor 402 may include more or fewer keyways 406.

The shaft 404 includes an internal fluid path 410 extending through partof the shaft 404. The internal fluid path 410 is coupled in fluidcommunication with an input port 412 located at one end of the shaft404. Internal fluid path 410 includes exit ports 414. The internal fluidpath 410 includes a first portion 416 extending substantiallylongitudinally through the rotor 402 and second portions 418 extendingsubstantially radially through the rotor 402 between the first portion416 and the fluid exit ports 414. The internal fluid path 410 isillustrated with a generally circular cross-section, but may have anysuitable cross-section, including, for example, an ellipticalcross-section.

The keyways 406 are coupled in fluid communication to internal fluidpath 410 via the exit ports 414. Accordingly, coolant may flow throughinternal fluid path 410 and into (and through) the keyways 406. Thecoolant contacts portions of the rotor 402 in the keyways 406 to removeheat from the rotor 402 during operation of an electric machineincorporating the rotor assembly 400.

The rotor 402 includes fluid passageways 426. The fluid passageways 426extend longitudinally through the rotor 402 from end to end. The fluidpassageways 426 provide another path through which coolant may flow tocontact different portions of the rotor 402 to remove heat from therotor 402.

The rotor assembly 400 includes two end plates 420 coupled to opposingends of the rotor 402. Each end plate 420 cooperatively defines with therotor 402 a fluid passage 422 between the end of the rotor 402 and theend plate 420. The fluid passage 422 is connected in fluid communicationwith the keyways 406 to permit coolant in the keyways 406 to contact theend of the rotor 402 during operation of an electric machineincorporating the rotor assembly 400. The fluid passage 422 alsoconnects the keyways 406 with the fluid passageways 426. Accordingly,coolant may flow from the keyways 406, through the fluid passage 422,and into (and through) the fluid passageways 426.

Each end plate 420 includes orifices 424 extending through the end plate420. The orifices 424 are in fluid communication with the fluid passage422 to permit coolant flowing through the rotor assembly 400 to exit therotor assembly 400. Although illustrated with two such end plates 420with orifices 424, the rotor 402 may include a single end plate 420, mayinclude one end plate 420 with orifices 424 and another end plate 420without orifices 424, may include endplate(s) 420 with more or fewerorifices 424, etc.

In operation, coolant is pumped into the internal fluid path 410 in theshaft 404. The coolant travels longitudinally down the shaft 404 andthen radially toward the exit ports 414. Coolant then enters the keyways406 and travels through the keyways 406 toward both ends of the rotor402. During this passage through the keyways 406, the coolant is incontact with the rotor 402 and removes some heat from the rotor 402. Thecoolant enters the fluid passage 422 and contacts the ends of the rotor402, removing additional heat from the rotor 402. Some of the coolant isthen expelled from the rotor assembly 400 through the orifices 424 inthe end plates 420, while some of the coolant enters the fluidpassageways 426. The coolant travels through the fluid passageways 426,removing additional heat from the rotor 402. Coolant exits the fluidpassageways 426 into the fluid passage 422 adjacent one of the orifices424 and may be expelled from the rotor through the orifice 424. Theexpelled coolant is collected (such as via drainage ports 143 if therotor assembly 400 is used in electric motor assembly 100 shown in FIGS.1-8) and recirculated to the input port 412. During the recirculation,the coolant may be processed to release at least some of the heat thecoolant received from the rotor 402. Any suitable process for loweringthe temperature of the coolant by allowing the coolant to release heatmay be used. For example, the coolant may be cooled using a radiator, afan, thermally conductive tubing, a heat sink, a combination of suchcooling techniques, etc.

In FIGS. 18 and 19, yet another example embodiment of a rotor assembly500 for use in an electric motor assembly is illustrated. The rotorassembly 500 may be used in electric motor assembly 100 or electricmotor assembly 200, or in any other suitable motor assembly, with orwithout the stator cooling features disclosed herein.

The rotor assembly 500 includes a rotor 502 and a shaft 504 coupled tothe rotor 502.

The shaft 504 includes an internal fluid path 510 extending through partof the shaft 504. The internal fluid path 510 is coupled in fluidcommunication with an input port 512 located at one end of the shaft504. Internal fluid path 510 includes exit ports 514. The internal fluidpath 510 includes a first portion 516 extending substantiallylongitudinally through the rotor 502 and second portions 518 extendingsubstantially radially through the rotor 502 between the first portion516 and the fluid exit ports 514. The internal fluid path 510 isillustrated with a generally circular cross-section, but may have anysuitable cross-section, including, for example, an ellipticalcross-section.

The rotor 502 includes fluid passageways 526. The fluid passageways 526extend longitudinally through the rotor 502 from end to end. The fluidpassageways 526 are coupled in fluid communication to internal fluidpath 510 via the exit ports 514. Accordingly, coolant may flow throughinternal fluid path 510 and into (and through) the fluid passageways526. The coolant contacts portions of the rotor 502 in the fluidpassageways 526 to remove heat from the rotor 502 during operation of anelectric machine incorporating the rotor assembly 500.

The rotor assembly 500 includes two end plates 520 coupled to opposingends of the rotor 502. Each end plate 520 cooperatively defines with therotor 502 a fluid passage 522 between the end of the rotor 502 and theend plate 520. The fluid passage 522 is connected in fluid communicationwith the fluid passageways 526 to permit coolant in the fluidpassageways 526 to contact the end of the rotor 502 during operation ofan electric machine incorporating the rotor assembly 500.

Each end plate 520 includes orifices 524 extending through the end plate520. The orifices 524 are in fluid communication with the fluid passage522 to permit coolant flowing through the rotor assembly 500 to exit therotor assembly 500. Although illustrated with two such end plates 520with orifices 524, the rotor 502 may include a single end plate 520, mayinclude one end plate 520 with orifices 524 and another end plate 520without orifices 524, may include endplate(s) 520 with more or fewerorifices 524, etc.

In operation, coolant is pumped into the internal fluid path 510 in theshaft 504. The coolant travels longitudinally down the shaft 504 andthen radially toward the exit ports 514. Coolant then enters the fluidpassageways 526 and travels through the fluid passageways 526 towardboth ends of the rotor 502. During this passage through the fluidpassageways 526, the coolant is in contact with the rotor 502 andremoves some heat from the rotor 502. The coolant enters the fluidpassage 522 and contacts the ends of the rotor 502, removing additionalheat from the rotor 502. The coolant is then expelled from the rotorassembly 500 through the orifices 524 in the end plates 520. Theexpelled coolant is collected (such as via drainage ports 143 if therotor assembly 500 is used in electric motor assembly 100) andrecirculated to the input port 512. During the recirculation, thecoolant may be processed to release at least some of the heat thecoolant received from the rotor 502. Any suitable process for loweringthe temperature of the coolant by allowing the coolant to release heatmay be used. For example, the coolant may be cooled using a radiator, afan, thermally conductive tubing, a heat sink, a combination of suchcooling techniques, etc.

In FIGS. 20-26 yet another example embodiment of a rotor assembly 600for use in an electric motor assembly is illustrated. In FIGS. 23-26,the rotor assembly 600 is illustrated assembled in electric motorassembly 100. The rotor assembly 600 may, however, be used in electricmotor assembly 200 or in any other suitable motor assembly, with orwithout the stator cooling features disclosed herein.

The rotor assembly 600 includes a rotor 602 and a shaft 604 coupled tothe rotor 602.

The rotor 602 includes fluid passageways 626. The fluid passageways 626extend longitudinally (i.e., in the axial direction) through the rotor602 from end to end. The coolant contacts portions of the rotor 602 inthe fluid passageways 626 to remove heat from the rotor 602 duringoperation of an electric machine incorporating the rotor assembly 600.

The rotor assembly 600 includes two end plates 620A and 620B(collectively and/or generally endplates 620) coupled to opposing endsof the rotor 602. End plate 620B includes orifices 621 aligned with thefluid passageways 626 and extending through the end plate 620B. Theorifices 621 permit coolant flowing through the rotor assembly 600 toexit the rotor assembly 600. An impeller 628 (e.g., a fan, etc.) with afluid port 630 is coupled to the end plate 620A. The fluid port 630 isin fluid communication with the fluid passageways 626. When the shaft604 and the endplate 620A are rotated, the impeller 628 rotates anddraws coolant into the fluid port 630, and through the fluid passageways626 through the rotor 602, to remove heat from the rotor 602.

The coolant may be any suitable coolant, including, for example, oil,air, oil and air, etc.

In operation, the shaft 604, rotor 602 and end plates 620 are rotated.Because of the rotation of the end plate 620A, the impeller 628 drawscoolant in through the fluid port 630 and into the fluid passageways626. The coolant travels through the fluid passageways 626 toward theend plate 620B. During this passage through the fluid passageways 626,the coolant is in contact with the rotor 602 and removes some heat fromthe rotor 602. The coolant is then expelled from the rotor assembly 600through the orifices 621 in the end plate 620B. The expelled coolant iscollected (such as via drainage ports 143 if the rotor assembly 600 isused in electric motor assembly 100) and recirculated. During therecirculation, the coolant may be processed to release at least some ofthe heat the coolant received from the rotor 602. Any suitable processfor lowering the temperature of the coolant by allowing the coolant torelease heat may be used. For example, the coolant may be cooled using aradiator, a fan, thermally conductive tubing, a heat sink, a combinationof such cooling techniques, etc.

Another example electric motor assembly 700, according to one or moreaspects of the present disclosure will be described with reference toFIGS. 27-30.

The assembly 700 includes a housing 702 and a stator 704. The stator 704includes a stator core 706 with windings having end turns 708 around thestator core 706. The stator core includes an outer surface 710.

The housing 702 includes an inner surface 712 (best seen in FIGS. 28 and29). The inner surface 712 encloses the stator 704. Although theillustrated inner surface 712 encloses all of the stator 704, thehousing 702 may include an inner surface 712 that encloses less than allof the stator 704.

The inner surface 712 of the housing 702 engages (e.g., contacts,couples with, is connected to, etc.) the outer surface 710 of the statorcore 706. A fluid passage 714 is cooperatively defined by the outersurface 710 of the stator core 706 and a recessed channel 715 in theinner surface 712 of the housing 702. The fluid passage 714 permits acoolant (not illustrated) in the fluid passage 714 to contact portionsof the outer surface 710 of the stator core 706 to remove heat from thestator core 706 during operation of the electric motor assembly 700.

The coolant may be any suitable fluid for transferring heat. The coolantmay be, for example, oil, air, a mixture of oil and air, etc.

The illustrated recessed channel 715, and accordingly the fluid passage714, is generally S-shaped and traverses circumferentially and axiallyaround at least part of the housing 702 along a central portion of thestator core 706. The fluid passage 714 may traverse around the entirecircumference of the housing 702, or may traverse less than the entirecircumference of the housing 702. Additionally, the fluid passage 714may be oriented along the length of the housing 702 (e.g. substantiallyperpendicular to the illustrated recessed channel 715). The fluidpassage 714 may be located offset from a central portion of the statorcore 706. Alternatively, or additionally, the fluid passage 714 maytraverse the housing 702 both circumferentially and lengthwise, with noparticular direction (e.g., random, meandering, etc.), etc.Additionally, the fluid passage 714 may have any suitable shape and isnot limited to the particular shape shown in FIG. 28. The fluid passage714 may be symmetrical, asymmetrical, a combination of symmetrical andasymmetrical, etc. Additionally, or alternatively, the assembly 700 mayinclude more than one fluid passage 714. For example, there may be afluid passage 714 on each half of the housing 702 (e.g., around oppositesides of the stator core 706).

The fluid passage 714 includes several flow disruptors 713. The flowdisruptors 713 project into the fluid passage 714 from an edge of therecessed channel 715. Thus, each flow disruptor 713 changes the crosssectional area of the fluid passage 714 in the area where the flowdisruptor 713 is located. The flow disruptors 713 also interrupt thesmooth path through the passage 714 that the coolant would otherwisetake. Hence, the flow disruptors 713 disturb the flow of coolant throughthe fluid passage 714 and generate turbulence in the coolant. Thisturbulence may cause the coolant to mix or stir within the fluid passage714. The mixing or stirring of the coolant increases a heat transfercoefficient of the coolant adjacent the flow disruptors 713 within thefluid passage 714 and therefore permits greater transfer of heat fromthe stator core 706 to the coolant. This may result in better thermaltransfer from the stator to the coolant.

The flow disruptors 713 are located in portions of the fluid passage 714that are likely to have a low heat transfer coefficient (e.g., U bendsor straight passages in the fluid passage 714) and therefore adjacent toareas of the stator core 706 that may have higher temperatures thanother portions of the stator core 706. Thus, areas of the stator core706 that are likely to have higher temperatures may have additional heattransferred to the coolant due to the presence of the flow disruptors713. Alternatively, or additionally, the flow disruptors 713 may bepositioned in any other portion of the fluid passage to generallyincrease the heat transfer from the stator core 706 to the coolant.

The illustrated flow disruptors 713 are generally triangular shaped flowdisruptors 713 extending from an edge of the recessed channel 715 intothe fluid passage 714 and extending from the bottom of the recessedchannel 715 to about the inner surface 712 of the housing 702. The flowdisruptors 713 may have any other suitable shape, including, forexample, rectangular, square, semicircular, ellipsoid, etc. The size ofthe flow disruptors may also be any suitable size. The flow disruptors713 may, for example, extend a greater or lesser distance into the fluidpassage, may not extend completely to the inner surface 712 and/or thebottom of the recessed channel 715, etc. Furthermore, the flowdisruptors 713 need not all be the same shape or have the same size. Theflow disruptors 713 may have different sizes and shapes as desired toproduce different affects on the flow of coolant through the fluidpassage 714.

The stator 704 is a laminated stator. The stator core 706 is constructedof a plurality of stator laminations (not separately illustrated)laminated together. The stator laminations have outer edges (whichcooperatively form at least part of the outer surface 710 of the statorcore 706). The fluid passage 714 is configured to permit coolant in thefluid passage 714 to contact the outer edges of the stator laminations.

The assembly 700 includes a fluid inlet 716 in fluid communication withthe fluid passage 714. The assembly 700 also includes a fluid outlet 718in fluid communication with the fluid passage 714. A fluid collectionarea 720 is located adjacent the fluid outlet 718. The fluid outlet 718and the fluid collection area 720 are located below the stator 704.

During operation of the electric motor assembly 700, coolant enters theassembly through the fluid inlet 716 and flows through the fluid passage714 toward the fluid outlet 718. While flowing in the fluid passage 714,the coolant is in direct contact with the outer surface 710 of thestator core 706. More particularly, the coolant is in direct contactwith the stator laminations. Heat is transferred by this contact fromthe stator core 706 to the coolant. Generally, the coolant exits thefluid passage 714 through the fluid outlet 718. Some of the coolant maybe directed elsewhere in the assembly 700 instead of exiting the fluidoutlet 718, as will be discussed below. The coolant that exits the fluidoutlet 718 is returned to the fluid inlet 716. During the recirculationto the fluid inlet 716, the coolant may be processed with at least oneheat exchanger to release at least some of the heat the coolant receivedfrom the stator core 706. Any suitable process for lowering thetemperature of the coolant by allowing the coolant to release heat maybe used. For example, the coolant may be cooled using a radiator, a fan,thermally conductive tubing, a heat sink, a combination of such coolingtechniques, etc.

The assembly 700 includes a first end shield 722 and a second end shield724. A first wall 726 is positioned between the first end shield 722 andthe stator 704. A second wall 728 is positioned between the second endshield 724 and the stator 704. The first wall 726 and the first endshield 722 cooperatively define a first fluid chamber 730 and the secondwall 728 and the second end shield 724 cooperatively define a secondfluid chamber 732. Each of the first and second walls 726, 728 includesa plurality of orifices (e.g., holes, slots, openings, etc.). Althoughnot illustrated in FIGS. 27-30, the walls 726, 728 may include more orfewer orifices (with similar or different configurations) than the walls126, 128 and orifices 134 illustrated in the example of FIG. 8.

In operation of the assembly 700, coolant flows into the first andsecond fluid chambers 730, 732 and through the orifices. The orificesare configured (e.g., shaped, sized, aimed, etc.) to direct the coolantonto the end turns 708 of the stator 704 to remove heat from the endturns 708. The orifices may be configured to spray coolant on an outerside 736 of the end turns 708, on an inner side 738 of the end turns708, and/or on a face 740 of the end turns 708.

The coolant to be sprayed by the orifices is some of the same coolantthat flows through the fluid passage 714. As discussed above, coolantflows through the fluid passage 714 toward the fluid outlet 718. Most ofthe coolant exits the fluid passage 714 through the fluid collectionarea 720 and the fluid outlet 718. Some or all of the coolant, however,is diverted into a transfer port 742 located near the fluid outlet 718.The transfer port 742 is in fluid communication with at least one of thefluid chambers 730, 732. For example, the transfer port 742 illustratedin FIG. 28 transfers coolant to the first fluid chamber 730. A similartransfer port 742 on the other half of the housing 702 will providecoolant to the second fluid chamber 732. Alternatively, a singletransfer port (and/or more than two transfer ports) may provide coolantto both fluid chambers 730, 732. Similarly, more than one transfer portmay provide coolant to a single fluid chamber 730, 732. Alternatively,or additionally, coolant may be provided to the first and second fluidchambers 730, 732 separately from the coolant in the fluid passage 714.

Coolant sprayed onto the end turns 708 drips, splashes, etc. off the endturns 708 and is collected by drainage ports 743. The drainage ports 743direct the coolant into the fluid collection area 720. Alternatively, oradditionally, coolant sprayed by the orifices may be collectedseparately from coolant passed through the fluid passage 714.

The coolant is forcefully circulated through the assembly 700 (and moreparticularly, through the fluid passage 714, transfer port 742, etc.)using pressure. The pressure and speed of the coolant may be varied toachieve desired cooling, desired spray from the orifices, etc.Alternatively, or additionally, the coolant may be circulated by anyother suitable means (including, e.g., by gravity).

The cooling features discussed above are generally directed to coolingthe stator 704. The assembly 700 may also include features generallydirected to cooling a rotor 744. For example, the rotor 744 includes afluid passage 746 extending through part of the rotor 744. Coolant maytravel through the fluid passage 746 to contact one or more portions ofthe rotor 744 to remove heat from the rotor 744 during operation of theassembly 700. Other suitable rotors, including rotors without a fluidpassage 746, rotors according to other embodiments discussed herein,etc., may be used in the assembly 700 without departing from the scopeof this disclosure.

The assembly 700 includes first and second bearings 748, 750. The firstend shield 722 includes a first fluid passage 752 connected in fluidcommunication with the first fluid chamber 730 for supplying coolant tothe first bearing 748 to remove heat from the first bearing 748 andlubricate the first bearing 748. The second end shield 724 includes asecond fluid passage 754 connected in fluid communication with thesecond fluid chamber 732 for supplying coolant to the second bearing 750to remove heat from the second bearing 750 and lubricate the secondbearing 750.

Another example electric motor assembly 800, according to one or moreaspects of the present disclosure will be described with reference toFIGS. 31-35.

The assembly 800 includes the housing 702 and stator 704 described abovewith reference to FIGS. 27-30. The assembly includes the rotor assembly600 described above with reference to FIGS. 20-26.

The assembly 800 includes a first end shield 822 and a second end shield824. The first wall 726 is positioned between the first end shield 822and the stator 704. The second wall 728 is positioned between the secondend shield 824 and the stator 704. The first wall 726 and the first endshield 822 cooperatively define the first fluid chamber 730 and thesecond wall 728 and the second end shield 824 cooperatively define thesecond fluid chamber 732. Each of the first and second walls 726, 728includes the plurality of orifices (e.g., holes, slots, openings, etc.)for directing coolant from the fluid chambers 730, 732 to the end turns708 of the stator 704.

The assembly 800 includes the first and second bearings 748, 750. Thefirst fluid passage 752 is connected in fluid communication with thefirst fluid chamber 730 for supplying coolant to the first bearing 748to remove heat from the first bearing 748 and lubricate the firstbearing 748. The second fluid passage 754 connected in fluidcommunication with the second fluid chamber 732 for supplying coolant tothe second bearing 750 to remove heat from the second bearing 750 andlubricate the second bearing 750.

The assembly 800 includes a bearing cap 856 attached to the second endshield 824 adjacent the second bearing 750. The bearing cap 856 includesat least one orifice 858 (e.g., hole, slot, opening, etc.). A cap fluidpassage 860 is connected in fluid communication with the second fluidchamber 732 (via the second fluid passage 754) and the bearing caporifice 858. A plug 862, possibly including an orifice, may be insertedinto the second fluid passage 754 to redirect some or all of the coolantin the second fluid passage 754 to the cap fluid passage 860. Thus,coolant may flow from the second fluid chamber 732 to the bearing caporifice 858. The bearing cap orifice 858 is configured (e.g., shaped,sized, aimed, etc.) to direct the coolant at the rotor 602. The bearingcap 856 may include more or fewer orifices 858, including no orifice858, than is illustrated in FIGS. 33 and 35 and/or the configuration oforifice 858 may differ. Further, in other embodiments, coolant may bedirected at the rotor 602 without employing or directing coolant throughthe bear cap 856 (e.g., the orifice 858 may be formed through adifferent component, or other means may be employed for directingcoolant to the rotor).

More specifically, the orifice 858 directs the coolant toward the endplate 620A of the rotor 602. As described above, the end plate 620Aincludes the impeller 628 (e.g., fan, impeller, etc.) and the fluid port630 in fluid communication with fluid passageways 626 through the rotor602. When the shaft 604 and the endplate 620A are rotated, the impeller628 draws coolant (including the coolant directed at the end plate 620Aby the orifice 858) into the fluid port 630 and through the fluidpassageways 626 through the rotor 602 to remove heat from the rotor 602.The coolant may include any suitable coolant, including, for example,oil, air, oil and air, etc.

Another example electric motor assembly 900, according to one or moreaspects of the present disclosure will be described with reference toFIGS. 36-39.

The assembly 900 includes a housing 902 and a stator 904. The stator 904includes a stator core 906 with windings having end turns 908 around thestator core 906. The stator core includes an outer surface 910. In thisparticular example, the assembly 900 is a switched reluctance motorassembly.

The housing 902 includes an inner surface 912 (best seen in FIGS. 37 and38). The inner surface 912 encloses the stator 904. Although theillustrated inner surface 912 encloses all of the stator 904, thehousing 902 may include an inner surface 912 that encloses less than allof the stator 904.

The inner surface 912 of the housing 902 engages (e.g., contacts,couples with, is connected to, etc.) the outer surface 910 of the statorcore 906. A fluid passage 914 is cooperatively defined by the outersurface 910 of the stator core 906 and a recessed channel 915 in theinner surface 912 of the housing 902. The fluid passage 914 permits acoolant (not illustrated) in the fluid passage 914 to contact portionsof the outer surface 910 of the stator core 906 to remove heat from thestator core 906 during operation of the electric motor assembly 900.

The coolant may be any suitable fluid (i.e., a liquid or gas) fortransferring heat. The coolant may be, for example, oil, air, a mixtureof oil and air, etc.

The illustrated recessed channel 915, and accordingly the fluid passage914, traverses along a central portion of the stator core 906. The fluidpassage 914 may traverse around the entire circumference of the housing902, or may traverse less than the entire circumference of the housing902.

As best shown in FIG. 38, the fluid passage 915 is configured to directcoolant in a first circumferential direction (e.g., counter-clockwise)around the housing (and thus around the stator) before reversingdirections to direct the coolant in a second circumferential direction(e.g., clockwise). Thus, the direction of coolant flow alternates backand forth along the length of the housing (and stator).

Additionally, the fluid passage 914 may traverse the entire length ofthe housing 902 or may traverse less than the entire length of thehousing 902. The fluid passage 914 may be oriented along thesubstantially perpendicular to the illustrated recessed channel 915. Thefluid passage 914 may be located offset from a central portion of thestator core 906. Alternatively, or additionally, the fluid passage 914may traverse the housing both circumferentially and lengthwise, with noparticular direction (e.g., random, meandering, etc.), etc.Additionally, the fluid passage 914 may have any suitable shape and isnot limited to the illustrated shape. The fluid passage 914 may besymmetrical, asymmetrical, a combination of symmetrical andasymmetrical, etc. Additionally, or alternatively, the assembly 900 mayinclude more than one fluid passage 914. For example, there may be afluid passage 914 on each half of the housing 902 (e.g., around oppositesides of the stator core 906).

The stator 904 is a laminated stator. The stator core 906 is constructedof a plurality of stator laminations (not separately illustrated)laminated together. The stator laminations have outer edges (whichcooperatively form at least part of the outer surface 910 of the statorcore 906). The fluid passage 914 is configured to permit coolant in thefluid passage 914 to contact the outer edges of the stator laminations.

The assembly 900 includes a fluid inlet 916 in fluid communication withthe fluid passage 914. The assembly 900 also includes a fluid outlet 918in fluid communication with the fluid passage 914. The fluid outlet 918is located below the stator 904.

During operation of the electric motor assembly 900, coolant enters theassembly through the fluid inlet 916 and flows through the fluid passage914 toward the fluid outlet 918. While flowing in the fluid passage 914,the coolant is in direct contact with the outer surface 910 of thestator core 906. More particularly, the coolant is in direct contactwith the stator laminations. Heat is transferred by this contact fromthe stator core 906 to the coolant. Generally, the coolant exits thefluid passage 914 through the fluid outlet 918. Some of the coolant maybe directed elsewhere in the assembly 900 instead of exiting the fluidoutlet 918, as will be discussed below. The coolant that exits the fluidoutlet 918 is returned to the fluid inlet 916. During the recirculationto the fluid inlet 916, the coolant may be processed with at least oneheat exchanger to release at least some of the heat the coolant receivedfrom the stator core 906. Any suitable process for lowering thetemperature of the coolant by allowing the coolant to release heat maybe used. For example, the coolant may be cooled using a radiator, a fan,thermally conductive tubing, a heat sink, a combination of such coolingtechniques, etc.

The assembly 900 includes a first end shield 922 and a second end shield924. A first wall 926 is positioned between the first end shield 922 andthe stator 904. A second wall 928 is positioned between the second endshield 924 and the stator 904. The first wall 926 and the first endshield 922 cooperatively define a first fluid chamber 930 and the secondwall 928 and the second end shield 924 cooperatively define a secondfluid chamber 932. The first and second walls 926, 928 include aplurality of orifices (e.g., holes, slots, openings, etc.). Although notillustrated in FIGS. 36-39, the orifices may be similar to the orifices134 in FIG. 8.

In operation of the assembly 900, coolant flows into the first andsecond fluid chambers 930, 932 and through the orifices. The orificesare configured (e.g., shaped, sized, aimed, etc.) to direct the coolantonto the end turns 908 of the stator 904 to remove heat from the endturns 908. The orifices may be configured to spray coolant on an outerside of the end turns 908, on an inner side of the end turns 908, and/oron a face of the end turns 908.

The coolant to be sprayed by the orifices is some of the same coolantthat flows through the fluid passage 914. For example, FIG. 39illustrates a cross section of a portion of the end shield 922 showingthe fluid inlet 916 that provides coolant to both the fluid passage 914and the first fluid chamber 930 (via a fluid passage 964). Some of thecoolant that passes through the fluid passage 914 is diverted to thesecond fluid chamber 932. The coolant in the first and second fluidchambers 930, 932 is sprayed by the orifices toward the end turns 908 ofthe stator 904.

Coolant sprayed onto the end turns 908 drips, splashes, etc. off the endturns 908 and is collected by drainage ports. The drainage ports directthe coolant to the fluid outlet 918.

The coolant is forcefully circulated through the assembly 900 (and moreparticularly, through the fluid passage 914, etc.) using pressure. Thepressure and speed of the coolant may be varied to achieve desiredcooling, desired spray from the orifices, etc. Alternatively, oradditionally, the coolant may be circulated by any other suitable means(including, e.g., by gravity).

The cooling features discussed above are generally directed to coolingthe stator 904. The assembly 900 may also include features generallydirected to cooling and lubricating bearings. As shown in FIG. 36, theassembly 900 includes a bearing 948. As shown in FIG. 39, the first endshield 922 includes a first fluid passage 952 connected in fluidcommunication with the first fluid chamber 930 for supplying coolant tothe bearing 948 to remove heat from the bearing 948 and lubricate thebearing 948.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the invention. Individual elements or features ofa particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the invention, and all such modificationsare intended to be included within the scope of the invention.

The invention claimed is:
 1. An electric motor assembly capable of beingcooled with a coolant, said motor assembly comprising: a rotor rotatableabout an axis; a stator including a stator core and windings wound aboutthe stator core, said stator core including opposite first and secondends spaced along the axis, said stator core presenting an outer surfaceextending between the ends, said windings including end turns positionedat the first end of the stator core; a housing enclosing at least aportion of the stator, said housing including an inner surface thatcooperates with the outer surface of the stator core to define a statorcooling passage through which coolant flows to remove heat from thestator core during operation of the assembly; and at least one orificefor directing coolant onto the end turns for removing heat from the endturns during operation of the assembly, said at least one orifice beingin fluid communication with the stator-cooling passage, said windingsincluding a second set of end turns positioned at the second end of thestator core, said housing inner surface cooperating with the outersurface of the stator core to define a second stator-cooling passagethrough which coolant flows to remove heat from the stator core duringoperation of the assembly, said assembly defining at least one secondorifice for directing coolant onto the second end turns for removingheat from the second end turns during operation of the assembly, said atleast one second orifice being in fluid communication with the secondstator-cooling passage.
 2. The electric motor assembly as claimed inclaim 1, said stator-cooling passage and said second stator coolingpassage each at least in part circumscribing the core, saidstator-cooling passage and said second stator cooling passage extendingin generally opposite circumferential directions.
 3. The electric motorassembly as claimed in claim 1, said stator-cooling passage including aplurality of fluidly interconnected, at least substantially S-shapedportions.
 4. The electric motor assembly as claimed in claim 1, saidstator-cooling passage directing coolant in alternating first and secondcircumferential directions, said first circumferential direction beingopposite the second circumferential direction.
 5. The electric motorassembly as claimed in claim 1, said stator-cooling passage at least inpart circumscribing the core.
 6. The electric motor assembly as claimedin claim 1, said end turns presenting a radially outer side, said atleast one orifice directing coolant onto the radially outer side.
 7. Theelectric motor assembly as claimed in claim 1, said at least one orificeconfigured to be downstream of the stator-cooling passage, such thatcoolant first flows through the stator-cooling passage to remove heatfrom the stator core and is then directed through the at least oneorifice to remove heat from the end turns.
 8. The electric motorassembly as claimed in claim 7, said assembly including a chamberextending between and fluidly interconnecting the stator-cooling passageand the at least one orifice.
 9. The electric motor assembly as claimedin claim 8, said chamber extending generally circumferentially.
 10. Theelectric motor assembly as claimed in claim 9, said chamber beinggenerally toroidal.
 11. The electric motor assembly as claimed in claim8, said housing at least in part defining the chamber.
 12. The electricmotor assembly as claimed in claim 11, said chamber in part defined by awall-like structure positioned between the housing and the stator, saidwall-like structure defining the at least one orifice.
 13. The electricmotor assembly as claimed in claim 12, said housing including a recessedportion in part constituting the chamber, said wall-like structure atleast substantially enclosing the recessed portion of the housing. 14.The electric motor assembly as claimed in claim 13, said wall-likestructure being positioned between the housing and the first end of thestator.
 15. The electric motor assembly as claimed in claim 14, saidhousing having an axial end, said wall-like structure being positionedaxially between the axial end of the housing and the first end of thestator.
 16. The electric motor assembly as claimed in claim 13, saidhousing including an endshield defining the recessed portion.
 17. Theelectric motor assembly as claimed in claim 12, said assembly includinga plurality of said orifices for directing coolant onto the end turnsduring operation of the assembly, said wall-like structure defining theorifices.
 18. The electric motor assembly as claimed in claim 17, saidorifices being arcuately spaced apart.
 19. The electric motor assemblyas claimed in claim 17, said wall-like structure being contoured todirect coolant via the orifices onto different portions of the endturns.
 20. The electric motor assembly as claimed in claim 8, saidassembly including a transfer port extending between and fluidlyinterconnecting the stator-cooling passage and the chamber, saidstator-cooling passage, said transfer port, and said chamber configuredsuch that coolant is directed exclusively from the stator-coolingpassage to the transfer port and exclusively from the transfer port tothe chamber.
 21. The electric motor assembly as claimed in claim 20,said housing defining the transfer port.
 22. The electric motor assemblyas claimed in claim 8, said assembly including an inlet, a fluidcollection area, and an outlet, said inlet, said stator-cooling passage,said at least one orifice, said fluid collection area, and said outletbeing sequentially fluidly interconnected and configured such thatcoolant flows from the inlet into the stator-cooling passage andthereafter to the at least one orifice, is directed onto the end turnsvia the at least one orifice and thereafter collects in the fluidcollection area, and drains from the fluid collection area to andthrough the outlet.
 23. The electric motor assembly as claimed in claim1, said housing inner surface defining a recessed channel that at leastin part constitutes the stator-cooling passage.